Got a wired situation crop up. A CEL. Using my reader, I get P0101. A MAF code. Done all kinds of things everything says to check. Still there. It shows up about every 3rd day.

Had a crazy idea. Maybe my HF reader isn't reading it right or isn't reading all the codes, so I stopped by an Oriley's and had them read the code. They got the same P0101 but they also got a P2BAC Oxides of Nitrogen Exceedance Deactivation of EGR.

The only reference I can find of this P2 code, is someone that fought it and finally figured out that it is caused by a lean situation and a filter changed fixed this. I have not changed the fuel filter, although I intend to, due to other surprise expenses sine acquiring this truck.

Any ideas or comments and or suggestions?

I will be changing the fuel filter, and the CEL only appears at highway speeds.